不同截留分子量超微滤膜处理地表水中膜污染的对比研究

Comparation study on the membrane fouling of ultrafiltration-microfiltrationmembranes with different molecular weight cut-off in surface water treatment

截留分子量是表征超微滤膜截留性能的重要参数,与膜污染行为密切相关.研究了150000、3000000两种不同截留分子量超微滤膜处理地表水过程的污染行为,研究结果表明,超微滤膜截留分子量越小,膜污染速率越低,不可逆污染占比越低.截留分子量小的超微滤膜,膜表面截留了更多的污染物,防止污染物进入膜孔内部,降低了不可逆污染程度.膜污染模式分析指出,截留分子量小的超微滤膜,污染行为更快地转换为滤饼层过滤模式,滤饼层可以进一步吸附截留水中污染物质,同时滤饼层更容易通过物理清洗去除,不可逆污染程度较低.

Molecular weight cut-off(MWCO)is an important parameter to characterize the cut-off performance of ultrafiltration membranes,which is closely related to membrane fouling behavior.In this paper,the fouling behavior of ultrafiltration membranes with different MWCO of 150000 and 3000000 in the process of treating surface water was studied.Results showed that the ultrafiltration membrane with lower MWCO got lower fouling rate and irreversible fouling.The ultrafiltration membrane with lower MWCO retained more foulants on the membrane surface,prevented the foulant with high molecular weight from entering the inside of the membrane pores and reduced irreversible fouling.The analysis of the.membrane fouling mode pointed out that the fouling behavior of the ultrafiltration membrane with lower MWCO changes to the cake layer filtration mode faster.The cake layer can further adsorb and retain foulant in the water.And the cake layer is easier to remove by physical cleaning,resulting lower irreversible fouling.